(1) Field of the Invention
The present invention relates to a cable connection interface for a rack mount type apparatus (rack mount apparatus) for use in, for example, an optical transmission apparatus, communication apparatus, information processing apparatus, measurement device or the like, and to a rack mount apparatus having this cable connection interface.
(2) Description of Related Art
In general, an optical transmission station (optical transmission terminal station, optical repeater station, optical reception terminal station) in an optical transmission network conducts the processing such as amplification, repeating, termination, add-drop or the like with respect to an optical signal. Moreover, a large number of optical cables (optical fibers) are brought into each optical transmission station which in turn, carries out the processing such as amplification, repeating, or the like with respect to an optical signal received through an optical cable, with a portion of the processed optical signal being again inputted to an optical cable while the remaining optical signal being, for example, packet-transmitted as an electric signal. The aforesaid amplification, repeating and others are conducted in a shelf. This shelf has, for example, a line accommodation or line termination function to carry out the interface processing such as branch, separation, termination, transfer, format conversion or the like with respect to the received optical signal.
In addition, a plurality of shelves are mounted as one unit on one rack (frame, equipment frame), and there is a requirement for an increase in mounting density of these shelves. In this case, the mounting density signifies the number of shelves one rack can accommodate, and it is equally referred to as packaging efficiency or accommodation efficiency.
Still additionally, the entire equipment in which a desired device works (or operates) in a state accommodated in a rack is referred to as a rack mount apparatus and, in particular, when the rack mount apparatus is equipped with a shelf(s), it is referred to as a rack mount shelf.
FIG. 12(a) is a perspective view of a common rack mount shelf (rack mount apparatus) viewed from its front surface side, and FIG. 12(b) is a perspective view of the same rack mount shelf viewed from its rear surface side. The rack mount shelf 100 shown in FIG. 12(a) is connected through a plurality of optical cables (interface cables) or electric signal cables to the other optical transmission station or the other shelf (not shown) in the same optical transmission station. Strip-like m1 (m1 represents a natural number) slots (insertion openings) 90 are formed in a front surface side of the shelf 100 so that each of the slots 90 allows the insertion of a substrate unit (plug-in unit, printed board unit or package) 91 having a plug-in function.
In addition, for example, as shown in FIG. 12(b), a connector section (interface connector unit) 120 including a plurality of connectors for the connection with a feeder (power supply) or the other shelf (not shown) is provided on a rear surface of the shelf 100.
Although the size of a rack is determined according to the industry standard, there is no determination in the size of the shelf 100 and, hence, the size of the shelf 100 is designed so as to match the size of the rack and is required to achieve the high-density mounting in one rack. For this reason, so far, there have been employed a method of reducing the size of the shelf 100 and a method of using Back-To-Back mounting which will be mentioned later.
First, although there is a design method of reducing the thickness (vertical width or height) of the shelf 100 for the size reduction, since an extra cable disposition panel for rolling an extra cable (unnecessary or redundant cable of an optical cable) thereon is attached onto a front surface of each shelf 100, limitation is imposed on the reduction of the thickness of the shelf 100. This is because, due to the high-density mounting, the extra cable disposition panel covers the front surfaces of the shelves 100 accommodated at upper and lower positions adjacent to each other. Concretely, if the front surfaces thereof are covered thereby, while each of the shelves 100 are in service, the worker cannot insert or extract a substrate unit 91 into or from each of the shelves 100 adjacent vertically to each other, so difficulty is experienced in conducting the operations such as restoration processing at the occurrence of a trouble, maintenance and replacement.
In the following description, an interface cable will sometimes be referred to as an optical cable or extra cable.
Moreover, the bend radius of the optical cable is required to be set at a value higher than the allowable bend radius so as to prevent the degradation of the total reflection of light in the interior of the optical cable and, further, in view of this restriction on the bend radius, there is a limit to the reduction of the thickness of the shelf 100.
Still moreover, the shelf 100 can internally include a fan unit 110 with a cooling fan, for example, under the slots 90 as shown in FIG. 12(a) for the purpose of heat radiation processing. When this fan unit 110 is set in the interior of the shelf 100, the vertical size of the shelf 100 increases, which leads to a decrease in mounting density of the shelf 100. Yet moreover, when the fan unit 110 is attached onto a side surface of the shelf 100, the horizontal width of the shelf 100 increases, which makes it difficult to achieve the size reduction of the shelf 100.
Accordingly, the size of the shelf 100 is determined on the basis of various factors including the dimension of the extra cable disposition panel, the bend radius of the optical cable, the dimension of the fan unit 110 and the mounting positions of the units. Moreover, the improvement of the respective factors by the designer enhances the mounting density of the shelf 100.
Thus, in the case of a construction of an optical transmission network, a competition point among the respective companies is “how to mount more shelves” on one rack, such as the number of shelves 100 and the locations thereof.
Secondly, a description will be given of a Back-To-Back mounting method which enhances the mounting density.
FIG. 13 is a partial perspective view showing a rack mount apparatus in the case of the Back-To-Back mounting, and each of two shelves 100 shown in FIG. 13 is mounted in the interior of a rack from a front-to-back direction. Moreover, the respective shelves 100 are fixedly secured to two columns 93 constituting the rack so that they makes a Back-To-Back state. Accordingly, the employment of this mounting method can enhance the mounting density and, hence, this Back-To-Back mounting method is extremely effective.
In general, in an optical transmission station, a large number of racks are placed on a floor in a state closed up in order to save the rack location space. Therefore, the installation of racks Back-To-Back-mounted makes it difficult to sufficiently secure the working space, which makes it extremely difficult to the worker to conduct the operations such as connection change of the connector section 120 provided on a rear surface of each of the shelves 100 or which makes it impossible to conduct the operations. Moreover, a difficult operation can impose a stress on an interface cable 150, which leads to damaging the interface cable 150. Accordingly, when the shelf 100 is in service, difficulty is encountered in carrying out various operations such as the insertion/extraction of the substrate unit 91 (FIG. 12(a)) according to an increase/decrease in the number of subscribers, connection change of the interface cable 150 involved in the insertion/extraction of the substrate unit 91 and maintenance/inspection of the shelves 100. In other words, since the two shelves 100 and the rack are fixed (fastened), difficulty is experienced in carrying out the change of the connection of the interface cable 150 without restriction.
For this reason, in order to avoid the damages of the interface cable 150 and to enable the change or setting of the connection state of the interface cable 150, a front access panel 140 into which a plurality of connectors (connection portions) 9 are inserted is provided at a bottom portion of each of the two shelves 100. Each of the connectors 9 is directly connected to each of one ends of the interface cable 150, and each of the other ends of the interface cable 150 is connected to a connector portion (not shown) on a rear surface of each of the shelves 100. Thus, the worker can accomplish the connection setting and connection change of the interface cable 150 from the front surface side of the shelf 100.
On the other hand, the method of additionally mounting the front access panel 140 in the shelf 100 also has a limitation on the mounting density. For example, in a case in which the front access panel 140 is placed at a lower portion of the shelf 100 (or an upper portion of the shelf 100, not shown) as shown in FIG. 13, the combination of the shelf 100 and the front access panel 140 causes an increase in vertical width H, which can suffer the degradation of the mounting density of the shelves 100. Meanwhile, although an access box having the same function as that of the front access panel 140 can also be set on a side surface of the shelf 100, as mentioned below with reference with FIG. 14, in the case of a small rack width, difficulty is encountered in setting the access box on a side surface of the shelf 100.
FIG. 14 is an illustration of one example of a shelf equipped with an access box, and a shelf 100a shown in FIG. 14 has an access box 140a into which a connector section 120 including a plurality of connectors are fitted and which is attached to a side surface thereof.
In most cases of rack width (portion denoted by L) taken by various manufactures (which will be referred to hereinafter as mainstream), it is a width of 23 inches (1 inch=approximately 2.54 cm). Accordingly, as a conventional rack, it is possible to employ an integrated type of the access box 140a and the shelf 100a as shown in FIG. 14.
On the other hand, recently, there has been a requirement for a small-sized rack. In particular, the employment of a shelf increases as an IP (Internet Protocol) packet transferring apparatus, and the mainstream of the rack width reaches a 19-inch width. For this reason, difficulty is encountered in securing an area (or space) for attaching the access box 140a onto a side surface of the shelf 100a. Moreover, a rack combining an IP packet transferring function and an optical transmission function is in increasing demand.
Accordingly, since the shelves 100 (100a) are mounted vertically in a line along a vertical direction of the rack, there exists a requirement for a flexible shelf mounting method having a large degree of freedom allowing the free selection of a size mounting method. This flexible mounting method requires, for example, a structure capable of separating the access box 140a and the shelf 100a so that a connection can easily made through a high-reliability interface cable 150 between the access box 140a and the shelf 100a. Therefore, a structure having less degree of freedom of the rack mounting, for example, an integrated structure between the access box 140a and the shelf 100a, is unsuitable in the case of a construction of an optical transmission system requiring abundant variations on the locations of the shelves 100a and the rack.
As mentioned above, according to the conventional techniques, with respect to the size reduction of the shelves 100, there is a limit to the reduction of the thickness of the shelf 100 and, hence, there is still a requirement for the high-density mounting of the shelves 100. Moreover, also in the case of the employment of a method of placing the front access panel 140 on an upper or lower surface of the shelf 100 or a method of attaching the access box 140a onto a side surface of the shelf 100a, which is for accomplishing the Back-To-Back mounting, difficulty is experienced in overcoming the limitations. Still moreover, there is no freedom of the change of the rack mounting method.
A large number of rack mount apparatuses have been proposed so far (for example, see Patent Documents 1 and 2)
The communication apparatus disclosed in the Patent Document 1 is such that a common shelf is provided and a rear access kit or front access kit is selectively mounted on the common shelf according to a station space. The front access kit has a plurality of connectors provided in the vicinity of a front surface thereof, and cables extending from outside line connectors are connected to the connectors from the rear side. The connectors are of a type in which a large number of pins are protrusively formed on the front side of the apparatus, and they are connected to different connector cables on the front side of the apparatus.
The front access terminal board of a communication apparatus disclosed in the Patent Document 2 is such that an extra portion is added to a cable within the apparatus so as to enable a connector assembly to slide in a front-to-back direction in a terminal section within an extra range.
The communication apparatuses disclosed in these Patent Documents 1 and 2 cannot achieve both the above-mentioned high-density mounting of shelves 100 and free change of the rack mounting method.
However, as described above, in the case of the employment of the conventional techniques, it is difficult to improve the mounting density of the shelves 100. Moreover, in the case of the employment of the Back-To-Back mounting method, there is a problem in that the operation for the connection of the connector section 120 becomes impossible.
In addition, in a case in which the front access panel 140 or the like is placed on an upper/lower surface or side surface of the shelf 100, there is a problem in that difficulty is experienced in securing the sufficient installation space and appropriate installation position for the front access panel 140 or the like and a large burden falls on the optical cable connection operation and others.
Nowhere in the above-mentioned Patent Documents 1 and 2 is there any disclosure of a technique for improving the mounting density and the free change of mounting position.
The present invention has been developed in consideration of these problems, and it is an object of the invention to provide a structured interface cable connection panel in a rack mount apparatus and a rack mount apparatus, capable of, in a rack mount apparatus, achieving an appropriate connection of an interface cable between a desired device such as a shelf and a panel such as a front access panel, changing an installation position of the front access panel and further shortening the work time taken for the connection between the panel and the interface cable.
[Patent Document 1] Japanese Patent Laid-Open No. SHO 63-221694
[Patent Document 2] Japanese Patent Laid-Open No. SHO 63-62300